There were 1,333 suicides among mental health patients in England in 2011 - up from 1,175 in 2010, according to new provisional statistics.
Recently, suicide and mental illness were thrust into the spotlight after Stephen Fry revealed he attempted suicide last year using pills and vodka.
Researchers from the National Confidential Inquiry into Suicide and Homicide by People with Mental Illness said that "current economic difficulties" are likely to be a contributory factor to the increase, with debts, housing and employment as driving concerns.
Professor Louis Appleby, director of the National Confidential Inquiry, said: "The increase in suicide among mental health patients is in line with an increase in the general population and is mostly likely due to the current economic circumstances.
"Although these are only early indicators, it would suggest services should try to address the economic difficulties of patients who might be at risk of suicide.
"Ensuring patients receive advice on debts, housing and employment could make a difference, while improvements in home treatment should now become a priority for suicide prevention. Particular caution is needed with home treatment for patients who live alone or are reluctant to accept treatment."
Janet Davies, executive director of nursing and service delivery for the Royal College of Nursing added: "Any suicide is a personal tragedy, and one whose effects can be felt by families for many years. Working to help people at risk of suicide is uniquely challenging, but the progress which has been made in preventing suicide by inpatients shows that the compassion and commitment of mental health staff does make a difference.
"Nurses will be very concerned about the rising number of people who are committing suicide while being treated at home. The reasons for this are highly complex, and the Government, NHS and clinicians must work together to understand as much as possible about how these tragedies can be prevented.
"Sadly, we know from past experience that many people do reach a crisis point in their mental health after a number of years of economic downturn. The mental health of the population provides a significant and urgent impetus for efforts to improve economic stability across the board. It also makes it more important than ever that services are available to meet the extra demand generated by the economic downturn."
The research, conducted by experts from the University of Manchester, found that the number of people murdered by mentally ill patients was 33 in England in 2010 - the lowest figure since 1997.
For advice or help, or if you have been affected by suicide, visit the Samaritans website.